Aerobiologia 17: 11–17, 2001. © 2001 Kluwer Academic Publishers. Printed in the Netherlands. 11 Airborne fungal spores colonising marbles exposed in the terrace of Messina Museum, Sicily Clara Urz` ı ∗ , Filomena De Leo, Paola Salamone & Giuseppe Criseo Institute of Microbiology, Faculty of Science, University of Messina, Villaggio S. Agata Messina, Italy ( ∗ author for correspondence, e-mail: urzicl@unime.it; fax: +39 090 392733) (Received 5 February 1999; accepted in final form 16 December 1999) Key words: airborne fungi, colonisation, contamination, marble Abstract Studies were carried out on the air and on Carrara marble blocks located in the terrace of Messina Museum, in order to know the likelihood of airborne fungal spores coming into contact with and colonising tridimensional objects. Our results showed there were not significant differences between airborne fungi circulating in spring and in autumn; Aspergillus, Penicillium, Fusarium, Alternaria, Cladosporium, Ulocladium, Aureobasidium, Phoma were the most common isolates. However, only few species were able to settle on the marble surfaces as demonstrated by their isolation after 2 and 6 years of exposition. 1. Introduction Airborne fungi occur as single units, spores and occa- sionally as hyphal fragments, conidiophores, asso- ciated with inorganic particles or as ‘bioaerosol’ (Comtois, 1990). Number and type of fungi vary with time of day, weather and seasonal fluctuation, geographical location, and with the presence of a local source of spores (Lacey, 1981). The transport and ultimate settling on the surfaces is affected by: (i) the physical properties of particles and/or of droplets (size, density and shape); (ii) the environmental parameters (magnitude of air move- ments, relative humidity, and temperature) and (iii) the bioreceptivity of the surface itself and nutrient avail- ability (Yang and Johanning, 1997; Guillitte, 1995; Urzì and Realini, 1998). Much of our knowledge on the behaviour of airborne spores comes from various studies on the epidemiology of plants, animals and human diseases, especially infections of the respiratory tract and allergy (Comtois, 1990; Angulo et al., 1996). Very little was reported on the impact of airborne fungi on monuments and rock surfaces in indoor and outdoor environments (Mandrioli and Zenotti Censoni, 1982). It is well known that once fungi settle on and colonise stone surfaces, they contribute to a great variety of alterations like black patinas, intergranular growth, marble sugaring, biopitting, etc. Most of the researches have dealt with fungi already settled on the rock surface and/or with ‘autochtonous mycoflora’ (Saiz-Jimenez, 1995; Urzì et al., 1995; Sterflinger and Krumbein, 1997). The aim of the present paper was to study the impact of airborne mycoflora on monument surfaces comparing the finding of airborne fungi on a tridimen- sional object with the one colonising freshly exposed Carrara marble blocks located in the terrace of Messina Museum. 2. Materials and methods 2.1 Sampling and counts of airborne fungi Airborne fungi were sampled in two different seasons, spring and autumn, using an impact-sedimentation method. In order to simulate the fungal impact with a three-dimensional object, Petri dishes (100 mm) containing three different cultural media (Dichloran Rose Bengal Chloramphenicol, DRBC, Commis- sione Normal, 1990; Glucose Mineral Agar, GMA, Eckhardt, 1988, plus dichlorane addition; Czapek dox Agar, CZ, Oxoid) were disposed on the 5 faces of a